Seal for borehole thermometer piston rods



SePf- 14 1954 l.. v. UHRIG ETAL SEAL EoR BoREHoLE THERMOMETER PIsToN RoDs Filed Oct. 20, 1950 INVENTORS. Leo V. Uhrig, By JQhn N. Atkins Jr.,

ATTORNEY.

Patented Sept. 14, 1954 AUNI'IELD STATES PATENT OFFICE SEAL FOR -BOREHOLE THERMOMETER PISTON RODS' Leo V. Uhri'g and John N. Atkins',

Tex., assignors,

Jr., Houston..

by mesne assignments. to

Standard il Development Company, Elizabeth, N. J., a corporation` ofz Delaware Application October 20, 1950.,.Seria1No. 191,204

object .of the present invention is the provisionv of! va-borehole thermometer of the character described employing mercury or a similar heat sensitiyeuid asa. medium for indicating changes .of` temperature by vchanges in volume, and provided Withmeans for eliminating the escape of mercury from the inner chambers thereof, and further provided with means for preventing the ingressv of ,'anyfiuid into the inner portions thereof.

Afurther object of the present invention vis to providean arrangement whereby the plug separatingthe measuring .and recording chambers .oi the present invention is not subjected to wear in operation. A further object is to provide an improvedisealing means aroundthe piston rod ,em-' ployedin the presenty device at the point at which` it passes through the aforementioned plug. .A

further object is to provide a, means for adjustingffthe tension on the `piston employed and for presettingrthe temperature range ofthe thermometer without dismantling the entire instrument.

.Further objects and advantages of the presenti invention Vwill appear from the following detailed .description of the accompanying drawing inwhich .'Fig; 1 is a `longitudinal section through the upper portion of the thermometer of the present invention;

Fig. 2 is a longitudinal section through the lower portion of said thermometer; and

Eig. 3 isa section of the upper portion of said thermometer taken along the line III-III of Fig. 1.

Referring to thev drawing in detail, the thermometeris made -in the form of a long cylindrical bomb which has two main interior chambers, the one being housed by casing I0 and the other being housed by casing I I. The chamber housed by casing I 0 will be referred to hereinafter as the piston chamber While the chamber housed by casing II will hereinafter be referred to as the recording chamber. Mounted within the recording chamber is a recording chart, together with the mechanism necessary to operate it.

2 Mounted within the temperatures on the recording chart mounted in the recording chamber.

Casing II] is an open-ended `cylinder interiorly threaded at both ends, namely at I2 and I3. Screwed into end I2 is plug I 4 provided with cupshaped projection I5 which is eX-ter-iorly threaded at :t6-and is provided with diametrically opposed slots I1 and Il to receive a pin I8 on which may be secured a wire linefor lowering the instrument into the borehole. of cup-shaped projection I5 is a cap IS provided with va longitudinal passage 2li through which a wire line may be passed for attachment to pin` L8. A gasket 2| is disposed between plug. I4 andy the upper `threaded end `I2. of casing I, saidt gasket being adapted to prevent the passage of fluids between these two members.

Screwed into end I3 of casing vHJ is a plug 22, said plug being provided with an exteriorly threaded stud 23 projecting into casing IIL-the other `end 24 .of plug 22 being also exteriorly threaded. An axial passage 25 extends through plug 22` and through stud 23, that portion of the passage25 passingthrough stud 23 being of greater diameter than the remainder of said passage.

thus forming a shoulder 26. I

Screw threaded von stud 23 is inner casing 2l of smaller external diameter than the inter-nal diameter of casing I-, whereby an annular space 28 is provided between the two casings. ,Screw threadedly engagedV with the upper end of casing A2-`I is a cap 29 having an axial passage ,30.`

extending therethrough, the upper end 3| of said passage being screw threaded and adapted to reiceive screw threaded plug 32 for closing said passage. A gasket 33 2.9 and inner casing 21 while gasket 34 is disposed between plug 22 andinner casingl. These gaskets provide` a uid-tight seal between the said parts. A gasket 35 is also disposed between casing L0 and plug 22 so as to prevent the movement of iiuid between said parts.

.Mounted in the interior of chamber 2 is ar spring anchor 36 and a piston 3l, a piston rod 38.being affixed to piston 31. Piston rod 38 extends through the axial passage 25 in plug 22. Anchored on spring anchor 3B and on vpiston 31 is a tension spring 39 which biases said members together. Spring anchor 36 is suspended within casing 21 by means of bolt 40 and nut 4I, the lower edge 42 of nut 4I abutting on plate 43 secured to upper edge 44 of casing 21 by means of screws 45. The upper end of bolt 40 has two diametrically opposed ilat surfaces which mate piston chamber isv the mechanism for operating the stylus employed to record.

Screwed onto the thread I6 is disposed between capv with the opening 46 in plate 43 as is best shown in Fig. 3. Therefore, when nut 4I is rotated, bolt 40 cannot rotate and thereby is caused to move vertically within casing 21. Vertical movement of bolt 40 in the aforesaid manner changes the tension on spring 39 so that any desired tension can be placed on this spring.

As previously pointed out, piston rod 38 extends through axial passage 25 of plug 22. Piston rod 38 does not t snugly within axial passage 25 and, accordingly, a sealing arrangement is provided in the enlarged portion of said passage within stud 23. This sealing means consists of a sleeve 41 which ts loosely around piston rod 38,

its lower edge 48 abutting against shoulder 26 of plug 22. The internal diameter of sleeve 41 is such that piston rod 38 does not contact the inner surface thereof when passing therethrough.

An O-ring 49 also circumscribes piston rod 38 and' is disposed on the upper edge 56 of sleeve 41. A retaining ring I, which has a central opening suiciently large so that the ring does not contact piston rod 38, circumscribes said piston rod above said O-ring and is held in place against said O-ring by means of screw 52. When screws 52 are tightened, O-ring 49 is compressed, thereby providing a duid-tight seal around piston rod 38 and preventing the iiow of heat sensitive fluid from the measuring chamber to the recording chamber.

Screw threaded on the end of piston rod 38 which projects into the recording chamber is a stud 53 provided with a recess 54 adapted to receive stylus spring 55, screws 56 securing stylus spring 55 to stud 53. A stylus 51, which is adapted to write on the surface of the record strip disposed within the interior of recording cylinder 58, is attached to the lower end of stylus spring 55.

Also disposed within casing I I is a clock mechanism 59 including 4shaft 68 which mechanically connects with recording drum 58 and rotates said drum. The lower end 6I of casing I I is closed by means of plug 62, gasket 63 being disposed between lower end 6I and plug 62. The lower end 64 of plug 62 may be bull-nosed as shown.

As shown in Fig. 1, the interior of casing 21 is completely filled with a heat sensitive fluid, such as mercury, as is the central passage 30 of plug 29 up to the threaded section 3l of said passage. This mercury filled space may be conveniently referred to as the inner chamber. It will be noted that O-ring 49 prevents passage of mercury or other heat sensitive fluid, past piston rod 38 while packing 34 and packing 33 prevent the egress of mercury past the threaded portions of casing 21. The upper threaded end 3I of passage 30 is closed by means of plug 66 carrying O-ring 65 recessed in its cylindrical surface adjacent its lower extremity, the upper end 32 of said plug being screwthreaded for engagement with the upper threaded end 3I of passage 30. With the screw-threaded end 32 of plug 66 in threaded engagement with the threaded end 3| of passage 30, O-ring 65 provides a fluid-tight seal around plug 66, thus preventing the escape of mercury through said passage. Once this seal is obtained, rotation of plug 66 in either direction causes corresponding displacement of piston 31, thus permitting the temperature range of the thermometer to be 4 preset without dismantling the entire instrument. The range over which the thermometer may be preset will depend, of course, on the distance through which plug 66 can be moved longitudinally within passage 30.

The annular space between casing I0 and inner casing 21 and cap 29 is also filled with mercury, preferably to a point near the upper end of cap 29. It will be noted that a clearance is provided between the upper end of cap 29 and plug I4 forming a chamber which is adapted to receive the overflow of mercury from the annular space aforementioned. The purpose of the mercury in this annular space is to take up the pressure which is exerted on casing I0 by the well iluids, thereby preventing this pressure from effecting any change in the volume of the inner chamber. A further purpose of the mercury in the annular chamber is to provide good heat conductance between casing Ill and members 21 and 29.

Having fully shown and described the device of our invention, what we wish to claim and to secure by Letters Patent is:

In a borehole thermometer which includes a recording chamber and a measuring chamber longitudinally aligned with respect to each other and separated by a plug defining a longitudinally extending passage therethrough and a rod extending into said chambers through said passage, said passage being of such diameter as to permit movement of said rod therethrough without contact between said rod and said plug, a sealing means comprising a sleeve circumscribing said rod and having an edge abutting on said plug, the internal diameter of said sleeve being suiliciently large to permit said rod to move freely therethrough out of contact therewith, an O-ring circumscribing said rod and abutting against the other edge of said sleeve, a retainer ring circumscribing said rod and abutting on said O-ring, the internal diameter of said ring being sufficiently large to permit said rod to move freely therethrough out of contact therewith, said retainer ring being removably secured to said plug by screws and adapted to compress said O-ring if urged in the direction of said sleeve whereby tightening of said screws causes said O-ring to provide a duid-tight seal between said rod and said plug.

References Cited in the ille of this patent UNITED STATES PATENTS Number Name Date 1,688,832 Sartakoff Oct. 23, 1928 1,770,559 Taylor July 15, 1930 2,183,126 Uhrig Dec. 12, 1939 2,401,379 Smith June 4, 1946 2,404,410 Smith July 23, 1946 2,518,540 Green Aug. 15, 1950 FOREIGN PATENTS Number Country Date 21,099 Great Britain Apr. 27, 1905 of 1904 OTHER REFERENCES Page 101 of Product Engineering, February 1945.- 

